Case 67

Presentation

A 41-year-old man is referred for management of a newly diagnosed melanoma on his left chest. The pathology report describes a 0.9-mm melanoma, Clark’s level III. He has light red hair, pale skin, and numerous freckles, and reports that his skin burns easily. He notes that his brother was treated for melanoma about 5 years ago and is now free of disease. On examination, he has a healing punch biopsy site on the left chest approximately 4 cm below the nipple, and no evidence of satellite lesions or in-transit disease. Regional node basins are clinically negative.

▪ Clinical Photograph

Figure 67.1

Physical Examination Report

On skin examination, a flat, irregularly shaped, pigmented lesion with color variegation is noted on the right side of his back.

Discussion

Most newly diagnosed melanoma patients present with thin (<1 mm) to intermediate (1 to 4 mm) Breslow thickness lesions. Treatment decisions are based on the pathology of the primary lesion, and review of the pathology slides by an experienced dermatopathologist is useful. Clinical evaluation includes an examination of node basins for evidence of lymphadenopathy, and skin examination for evidence of other suspicious skin lesions. For patients whose clinical examination reveals no evidence of distant disease, preoperative testing can be limited to standard chest x-ray and liver enzyme levels including lactate dehydrogenase (LDH).

Case Continued

Review of the outside pathology slides of the left chest lesion confirms the diagnosis of melanoma, 0.9 mm, Clark’s level III, and additionally notes the presence of histologic ulceration. A punch biopsy of the dark lesion on his right back shows melanoma in situ.

Diagnosis and Recommendation

This patient has two primary melanomas without clinical evidence of regional disease. He needs to undergo complete blood cell (CBC) count, evaluation of liver enzyme levels, and a chest x-ray as a basic staging work-up to exclude distant disease.

Case Continued

Chest x-ray and liver enzymes are normal.

▪ Approach

The melanoma in situ on his back should be excised with a measured margin of 5 mm. The melanoma on his chest is 1 mm or less in thickness, so a 1-cm measured margin is recommended. However, this thin, or T1, melanoma also has the feature of histologic ulceration, a poor prognostic feature. This is, therefore, a T1b melanoma, and lymphatic mapping
and sentinel node excision is also recommended to stage the regional nodes.

Discussion

Every primary melanoma requires wide local excision for local control. Margin width is determined by the thickness of the primary lesion. Melanoma in situ is conventionally excised with a 5-mm margin, although there are no prospective studies evaluating margin width for melanoma in situ, and it is unknown if narrower margins might be sufficient. A thin (1 mm or less) invasive melanoma is excised with a measured 1-cm margin, largely based on the results of the World Health Organization study. Intermediate thickness (1 to 4 mm) melanoma is preferably excised with a 2-cm measured margin, based on the Intergroup trial of 2-cm vs 4-cm margins for this group of patients. Thick (>4 mm) melanoma should be excised with a minimum 2-cm margin; it is unknown whether wider margins would be advantageous, and no prospective randomized trial is available to guide the choice of margin width.

The status of the regional nodes is the most important prognostic factor for patients with newly diagnosed melanoma. Sentinel node biopsy is a minimally invasive method of evaluating the regional nodes and should be offered to patients with melanomas >1 mm in thickness, and to patients with thinner melanomas (T1b) if they display adverse features of ulceration or deeper Clark’s level (IV or V). Sentinel node biopsy provides excellent prognostic information and aids in making appropriate treatment decisions. Knowledge of the pathologic nodal status is particularly important in patients who enter clinical trials of systemic adjuvant therapy to assure homogeneity of treatment groups.

Preoperative lymphatic mapping is essential for accurate sentinel node biopsy. An intradermal injection of technetium sulfur colloid is made in the nuclear medicine suite in normal-appearing skin directly adjacent to the biopsy site. Planar images are accrued to observe the accumulation of tracer in the sentinel nodes. For truncal primaries it is important to image all four node basins, because drainage to more than one basin is common. It is also important to look for unusual sites for the sentinel nodes: they have occasionally been described at sites outside of conventionally defined node basins, such as the triangular intramuscular space, the popliteal or epitrochlear fossa, and sites in the subcutaneous tissues between the primary site and the nearest node basin. The site of the sentinel node(s) detected on lymphoscintigraphy is marked on the overlying skin. In the operating room, a hand-held gamma probe is used to detect gamma emission from the technetium trapped in the node; this allows retrieval of the node through a small incision. Isosulfan blue 1% is injected intradermally around the original primary biopsy site to function as a visual aid in identifying the sentinel node.

Only gold members can continue reading. Log In or Register to continue